Neuroemergency trials require substantial infrastructure, close collaboration between pre-hospital, Emergency Department, and inpatient neurology/neurosurgery systems, and a dedicated group of physician, nurse, and paramedic researchers ready to invest time and resources to ensure trial success. These conditions strike suddenly, require immediate intervention in the pre-hospital or Emergency Department setting, and impair the self-awareness and decision-making capacity of the afflicted individual. The proposed Los Angeles Neurological Emergencies Treatment Trials Hub and Spoke Network brings together a consortium of 29 EMS Provider Agencies and 38 specialty receiving hospitals in the country's largest and most diverse County in a Hub and Spoke network designed to perform phase 3 NETT trials with high rates if recruitment and high quality of data collection and monitoring. The 4 aims of this proposal are to: 1) Perform high-quality NETT clinical trials in several different types of emergency neurological disorders afflicting adults or children throughout Los Angeles County; 2) Facilitate collaboration between emergency medicine physicians and neurological and neurosurgical disease specialists throughout Los Angeles County in trial design and execution; 3) Facilitate collaboration between the pre-hospital EMS system and acute receiving hospitals, including specialty receiving centers in trauma, stroke, and cardiac resuscitation, throughout Los Angeles County in trial design and execution; and 4) Ensure participation of a substantial number of patients with neurologic emergencies in NETT clinical trials, including women, Hispanic-Americans, African-Americans, and other minority populations.